Basically a port is simply a doorway into and out of your computer so that it can communicate with the big wide world. There are 1000s of them and your firewall will handle them automatically so they are not generally something you have to worry about. Ones that are not being used are kept locked to keep the baddies out.
You can read more herehttp://en.wikipedia.org/wiki/Computer_port_(software)
For interest, go to this site and scroll down to ShieldsUP where you can see how safe your computer ports arehttp://www.grc.com/default.htm
When a computer connects to say a webpage, we write in a big long thing like http://www.bleepingcomputer.com
, but your computer is only interested in numbers, so uses a system like a phone book to obtain the IP address it needs. If you have a record of an IP address, other than your own, type it in the address bar and press ENTER - see what happens.
Edited by rowal5555, 08 August 2008 - 07:05 PM.